476 



METALLURGY. (IRIDITTM, NICKEL, ALUMINUM.) 



vals, as the spoon-tests showed the necessity 

 for it. All the features of the amalgamation 

 of first-class ores are made to vary with the 

 richness of the ores, but with the second-class 

 ores the treatment is more methodical. Des- 

 puntes and the richer second-class ores are 

 generally charged in 1,100-pound lots, with 

 80 pounds of mercury, 2 per cent, of salt, 

 and 3 per cent, of sulphate of copper. The 

 poorer second-class ores, assaying 80 ounces 

 per ton and under, are charged with 40 pounds 

 of mercury and usually the same amount of salt 

 and sulphate of copper, and the runnings are 

 kept up for from a third to a half less time 

 than in the case of the first-class ores. When 

 squeezed and "retorted," the amalgam from 

 first-class ores usually yields a third part of pure 

 silver. The tailings of the ores are often quite 

 rich. Some tailings from first-class Ronces- 

 valles ore ran 79 ounces per ton. They are re- 

 duced by a chloridizing roasting. 



A very rich silver-producing district is situ- 

 ated in what are designated the Barrier Ranges, 

 in New South Wales, near where that colony 

 joins South Australia. The existence of the 

 silver-bearing ores was first discovered in 1876, 

 but they did not attract attention till about 

 1882. The influx of miners has aided in the 

 erection of a township, which is now known 

 as u Silverton." The mine at Silverton embraces 

 eleven claims, in which the ore consists of sul- 

 phides of lead, or argentiferous galena. Fifteen 

 shafts have been sunk, varying in depth from 30 

 feet to 75 and 130 feet. The larger Lakes Camp 

 group of mines are situated about twenty-eight 

 miles from Silverton, and consist of very rich 

 sulphides of silver. Ores from the Silverton 

 mines have yielded a clear profit of 12 or 

 $60 per ton, while two tons sent from the 

 Lakes Camp mines to England for assay were 

 sold for 600, or $3,000. 



Iridinm. The discovery by Mr. John Holland, 

 of Cincinnati, of methods suitable for making 

 the metal iridium promises to result in the de- 

 velopment of a new industry and in the addi- 

 tion of a new and valuable element to mechani- 

 cal resources. Iridium is chiefly obtained from 

 Russia and California, though it is also found 

 in other parts of the world. It is nearly al- 

 ways associated with platinum or gold, in small 

 grains or fine powder, the largest pieces being 

 of about the size of a grain of rice, generally 

 alloyed with platinum as platin-iridium, or 

 with osmium as osmiridium, or iridosmine. 

 Previously to Mr. Holland's experiments, it had 

 been possible to fuse it only at extremely high 

 temperatures in minute quantities that gave 

 globules of very small size. The only use for 

 which it had been found available was that of 

 pointing gold pens, for which the najtural pieces 

 were selected and fitted and then ground to a 

 proper shape. Mr. Holland, ceeking to obtain 

 larger pieces of iridium than were found in na- 

 ture, discovered that by adding phosphorus to 

 it, it became perfectly fusible, when it could be 

 poured out and cast into almost any desired 



shape. The resultant product was found to be 

 about as hard as the natural grains, and to have 

 all the properties of the metal itself, but to 

 contain from 7'52 per cent, to 7'74 per cent, of 

 phosphorus. At this stage of the research, 

 Mr. W. L. Dudley, of Cincinnati, began experi- 

 ments to find means of putting the product to 

 a more extended use in the arts. He discov- 

 ered that the phosphorus could be completely 

 removed, by heating the melted metal in a bed 

 of lime. His further investigations related to 

 the construction of appliances for grinding, 

 drilling, and sawing the metal, all of which 

 operations are performed with the aid of co- 

 rundum or diamond-dust. By means of these 

 improved processes, iridium has been made ap- 

 plicable to use in draw-plates for drawing gold 

 and silver wire ; knives for fine scales and bal- 

 ances; hypodermic needles ; the points of sty- 

 luses for manifold writing, and for surveyors' 

 and engineers' instruments, and all purposes 

 for which hardness, durability, andnon-corrosi- 

 bility are required; for the negative electrodes 

 of electric lights; and the electrical contact- 

 points of telegraphic apparatus. The later in- 

 vestigations, not yet completed, are upon meth- 

 ods of plating with iridium. 



Nickel. A valuable deposit of nickel-ore has 

 been discovered in Cottonwood Campus, 

 Churchill county, Nev. According to the de- 

 scription by Mr. Charles Bell, one of the discov- 

 erers, the ledge in which it occurs is perfectly 

 incased, runs 6,000feet northeast and southwest, 

 and is thirty feet wide between the walls, while 

 the mineral lies in veins, of which there are 

 thirteen, each from ten to thirty-five inches 

 wide. Specimens of the ore from the different 

 levels, amounting in all to thirty pounds in 

 weight, have been analyzed by Prof. Spencer 

 B. Newberry, and are pronounced by him the 

 finest masses of nickel-ore he has ever seen. 

 The sample from the greatest depth (80 feet) 

 consists of nearly pure niccolite. 



Alnminnm, Mr. Wm. Frishmuth, of Philadel- 

 phia, claims to have discovered a practicable pro- 

 cess for the commercial manufacture of alumi- 

 num. Instead of using metallic sodium, as in 

 the processes hitherto employed for the reduc- 

 tion of the chloride of aluminum, he employs a 

 vapor generated by heating a mixture of some 

 sodium compound with carbon or some other 

 reducing agent. The cheapness of this method, 

 as compared with those hitherto employed, is 

 illustrated by the statement that, while by 

 what is known as the De Ville method, to pro- 

 duce 20 pounds of aluminum, 50 pounds of 

 metallic sodium are required, at a cost of not 

 less than $150, in Mr. Frishmuth's process the 

 result is secured by the use of 115 pounds of 

 carbonate of sodium, costing one cent a pound. 

 Both processes employ the double chloride of 

 aluminum and sodium ; but Mr. Frishmuth has 

 taken out a patent for the use of the double 

 fluoride of the same metals. He has also intro- 

 duced improvements in making the double 

 chloride, by which its cost is greatly reduced, 



